Chile, Argentina: Adverse weather forecast across parts of central and southern Chile and western Argentina through at least July 22

Event

Severe weather is forecast across parts of central and southern Chile and western Argentina through at least July 22. A combination of thunderstorms, heavy rainfall, and strong winds are expected across parts of the affected area, as well as snow over elevated areas and possible tornadoes in central coastal areas of Chile. Heavy downpours may trigger flooding in low-lying areas and strong winds could cause property damage and power outages. Transport disruptions are likely in the region due to the adverse weather, especially in mountainous areas due to icy roads and reduced visibility caused by blowing snow.

As of July 21, the Chilean Meteorological Directorate and Argentinian National Meteorological Service (SMN) have issued the following weather warnings:

• Orange heavy rainfall warnings (the middle level on a three-tier scale): Parts of Maule and Nuble regions in Chile.

• Orange snowfall warnings: Parts of southwestern Mendoza and western Neuquen provinces in Argentina.

• Yellow heavy rainfall warnings: Parts of Biobio, Los Lagos, Los Rios, Maule, Metropolitana, Nuble, O'Higgins, and Valparaiso regions in Chile.

• Yellow snowfall warnings: Parts of Aysen, Los Lagos, and Magallanes regions in Chile.

• Yellow possible tornado warnings: Parts of Biobio, La Araucania, Los Lagos, Los Rios, and Nuble regions in Chile.

• Yellow thunderstorm warnings: Parts of Biobio, La Araucania, Los Lagos, Los Rios, Maule, and Nuble regions in Chile.

• Yellow strong wind warnings: Parts of Aysen, Biobio, La Araucania, Los Lagos, Los Rios, Maule, Metropolitana, Nuble, O'Higgins, and Valparaiso regions in Chile and parts of western La Rioja, central, southern, and western Mendoza, and much of San Juan provinces in Argentina.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Hazardous Conditions
The storms could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity across parts of the affected area. Where precipitation falls as rain, flash and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water, as well as in urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation could fall as snow in the higher elevations over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. Power outages could occur throughout the affected area.

Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.

The disruptive weather will likely cause some delays and cancellations at airports in affected areas. Authorities may temporarily suspend port operations along the west coast of Chile if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Argentina National Meteorological Service (SMN)
Chilean Meteorological Directorate